The present invention relates to an electric power tool including a motor whose rotor comprises a permanent magnet.
An electric power tool is known that is configured to drive-control a motor by setting a driving duty ratio for pulse width modulation (PWM)-controlling the motor in accordance with an operation amount of an operation switch, and by turning on/off switching elements in a drive circuit based on the driving duty ratio (see, for example, Japanese Unexamined Patent Application Publication No. 2009-050932).
In the electric power tool of this type, the driving duty ratio, which is a control amount of the motor, is set in accordance with the operation amount of a variable speed switch. Therefore, it is possible to control electric power to be supplied to the motor, and thus, to control the number of rotations of the motor, in accordance with the operation amount of the variable speed switch operated by a user.